Internal combustion engines may include engine blocks and cylinders heads. Each of the engine block and the cylinder head may be traversed by separate coolant circuits or at least predominantly separated cooling circuits. This engine cooling arrangement may be referred to as a split cooling system. In this way, the cylinder head, which may be thermally coupled to the combustion chamber wall, the intake manifold, and the engine block, which is thermally coupled to the friction points, can be cooled differently, if desired. The split cooling system (e.g., split coolant circuit) may attempt to cool the cylinder head during a warm-up period while reducing or in some cases inhibiting cooling of the engine block so that the engine block may achieve a desired operating temperature more quickly. In other words, the split coolant circuit may be thought of as a single cooling circuit for an engine in which the water jacket in the cylinder head is separated from the water jacket in the engine block via suitable mechanisms. In some embodiments, however, there may be low levels of leakage from the cylinder head water jacket to the engine block water jacket, wherein the leakage quantities are so small that one can nevertheless refer to this as a split coolant circuit.
FR 2 860 833 A1 discloses a cooling circuit of an internal combustion engine having at least one cylinder head and a cylinder housing, said cooling circuit being composed of at least three cooling passages. The circuit has a heat exchanger, a driver for a heat exchange medium, and at least one controller for controlling the flow of heat exchange medium through the cylinder head, the cylinder housing or the heat exchanger. The cooling circuit has at least three independent passages for engine cooling, wherein the first and second passages are arranged in the cylinder head and the third passage is arranged in the cylinder housing, and wherein the passages are independent of one another and comprise at least one inlet and one outlet, such that they permit an independent flow of the heat exchange medium through each of the passages of the cylinder head and of the cylinder housing. FR 2 860 833 A1 discloses that three controllers (e.g., valves) are provided in order to be able to regulate different circulations of the heat exchange medium. One controller is arranged at the inlet side and one controller is arranged at the outlet side. The third controller is connected to the other two controllers.
U.S. Pat. No. 5,385,123 discloses a split coolant circuit having a single thermostat which, in one embodiment, is arranged in an outlet line of the outlet side of a cylinder head to a pump, the line of which opens out at the inlet side in the cylinder head. A bypass and a block line branch off from the outlet line and extend into the engine block. The bypass leads to the pump. In the aforementioned embodiment, the thermostat is arranged in the branch of the three lines. During the warm-up phase, the thermostat closes the block line, wherein the bypass is fully open. When the thermostat is closed, the coolant flows through the bypass to the pump, and from there into the cylinder head. As the coolant temperature rises, the thermostat successively closes the bypass, such that the direct flow in the direction of the pump is continuously reduced, and is completely shut off when the bypass is completely closed. The coolant then flows out of the cylinder head through the outlet line and the block line into the engine block, which is connected to a cooler, and from there to the pump.
The Inventors have recognized several disadvantages with the split cooling design in U.S. Pat. No. 5,385,123 and the cooling system disclosed in FR 2 860 833. Firstly, the cooling systems disclosed in U.S. Pat. No. 5,385,123 and FR 2 860 833 may be bulky, thereby reducing the engine's compactness and increasing the size and cost of the engine. As a result, the cost of the engine may be increased. Moreover, the control system for controlling the 3 independent engine cooling passages in FR 2 860 833 may be complex and costly.
To solve at least some of the aforementioned problems a cooling system for an engine is provided. The cooling system includes a flow control element having an inlet in fluidic communication with an outlet of a cylinder head water jacket, a first outlet port in fluidic communication with a heat exchanger, and a second outlet port in fluidic communication with an inlet of an engine block water jacket.
In this way, the coolant may be flowed from the outlet of the cylinder head water jacket to the inlet of the engine block water jacket during some operating conditions and/or from the outlet of the cylinder head water jacket to a heat exchanger during other operating conditions. As a result, coolant may be flowed in series through the cylinder head and the engine block bypassing the heat exchanger, enabling a heater bypass line to be omitted from the cooling system, if desired. Moreover, the flow control element may be used to separately adjust the coolant flow through both the cylinder head water jacket and the cylinder block water jacket based on the engine's operating conditions.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings. It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
The figures are described in greater detail below.